Abstract
Dear Editors:
We read the interesting article “Telemedicine for the Reduction of Myocardial Infarction Mortality: A Systematic Review” written by de Waure et al. 1 that was published in this journal. Now we would like to make a few comments about the study.
The title of the article implies that patients with myocardial infarction have been included in the study, whereas only three of five selected articles are about patients suffering from myocardial infarction. Because coronary artery diseases may lead to different outcomes (e.g., stable angina, unstable angina, infarction, and even sudden death), this limitation should be considered. 2
Moreover, three articles were about studies conducted among the general population, and the setting of the study in two articles was a hospital; therefore the results could not be generalized to the population at large. Although studies conducted at a single hospital or clinic may be of great value, we should take the important point into account that it may be very tempting to look for patient information in one hospital and extrapolate the findings to all patients in the general population. However, this is not a legitimate approach because patients who come to a certain clinic or hospital often are not representative of all patients in the community. 3
In the sixth column of Table 1 in de Waure et al. 1 the types of intervention, which are not identical and comparable, are indicated. For example, Zanini et al. used two ambulances equipped with Lifepak 12 monitors, whereas in the article by Ortolani et al. the type of intervention was a diagnostic electrocardiogram at the patient's home (Lifepak 12) transmitted by a mobile system to a dedicated computer at the intensive care unit. An electrocardiogram may be affected by different equipment quality, speed, and accuracy, and this may lead to bias and affect the results. It is better to include articles with similar kinds of interventions.
Finally, this study is new and important, and we conclude that telemedicine is useful in reduction of myocardial infarction mortality and that all these studies reinforce the efficacy of telemedicine applications. But, we think if this study was on cost-benefit and cost-effectiveness analysis, its results could be more beneficial. 4
References
Response to Fayaz-Bakhsh and Manesh
Chiara de Waure, MD, MPH, MSc,1 Chiara Cadeddu, MD,1 Maria Rosaria Gualano, MD, MPH,2 and Walter Ricciardi, MD, MPH, MSc1
1Institute of Public Health, Catholic University of the Sacred Heart, Rome, Italy.
2Department of Public Health, University of Turin, Italy.
Dear Editors:
We thank Fayaz-Bakhsh and Manesh for their comments on our article “Telemedicine for the Reduction of Myocardial Infarction Mortality: A Systematic Review,” 1 which had the aim to summarize evidence on the impact of telemedicine systems on survival of patients with coronary heart disease (CAD). Fayaz-Bakhsh and Manesh raised several points about the comparability of studies and the interpretation of results that we would like to address.
As is clearly stated in the Introduction and the Methods sections, the aim of our review was to assess the efficacy of telemedicine facilities in the diagnosis and management of CAD and, in particular, acute myocardial infarction (AMI). The title of the review referred to AMI because the meta-analysis was performed with respect to the three studies 2 –4 addressing mortality in patients with AMI. Indeed, our article title is meant to spread the main message and result of our review. The other two studies 5,6 considered in our review did provide a proof of telemedicine benefits in improving survival of patients with established CAD. The goal of telemedicine use in these two last studies was to provide a timely and standardized approach to the management of symptoms in patients with established CAD.
As far as comparability is concerned, each of the three studies 2 –4 included in the meta-analysis did use the same equipment to obtain electrocardiograms (Lifepak 12; Medtronic Physio-Control, Redmond, WA). Because electrocardiograms were collected for diagnostic aims, it may be concluded that the standard protocol was used in each of the three studies. The only difference was concerning the setting: in the study of Ortolani et al., 4 ambulance personnel obtained electrocardiograms at the patient's home; in the study of Zanini et al., 2 electrocardiograms were obtained in the ambulance, whereas in the study of Limido et al., 3 electrocardiograms were obtained in the ambulance as well as in first-level hospitals.
With respect to generalizability, one study 5 drew patients from 11 hospitals, whereas the other one 6 did select patients from all intensive cardiac care units operating in the country. The other three studies 2 –4 were all performed on a territorial level. With this respect, we would like to specify that the Local Hospital Authority should be called more appropriately the Local Health Authority. Generalizability of results may indeed be supported.
Finally, as we concluded in the Discussion, further criteria, such as cost-effectiveness, should be considered in order to decide on allocation of resources. Cost-effectiveness analyses are sometimes performed alongside epidemiological studies. More commonly, modeling allows addressing cost-effectiveness of interventions on the basis of real practice resources and costs. Indeed, a good suggestion for future research would be to carry out ad hoc studies in order to make this kind of evaluation available.